1. Field of the Invention
The present invention relates to a delivery member useful for OA instruments, printers, and the like. The present invention also relates to an apparatus employing the delivery member.
2. Related Background Art
An apparatus such as an electrophotographic apparatus, a printer, and a facsimile machine comprises a delivery path for delivering an image-receiving medium like a recording paper sheet and a plastic sheet. The delivery path comprises a delivery member in a shape of a roller, a plate, a belt or the like.
In delivering the image-receiving medium, the delivery member is brought into contact with the image-receiving medium. Therefore the delivery member is required to be durable. Further, in high-speed recording and color recording, since the image-receiving medium needs to be delivered accurately, the surface of the delivery member is required to be uniform.
Conventional delivery members have a surface formed by one of the methods described below:
(a) a steel material is coated by spray coating with a coating liquid which contains a filler such as metal fine particles, PA0 (b) a steel material is plated with a metal, and has coated thereon with rubber, and is further coated with Teflon (registered trade name), PA0 (c) a steel material is roughened at the surface by sand blasting or laser machining, and then is plated with a metal, PA0 (d) a steel material is plated with a metal, and alumina is deposited thereon electrostatically, or PA0 (e) a steel material is plated with a metal, and is further subjected to composite plating to form a coating containing SiC, diamond, or the like.
The surface formed as above involves problems as below.
The delivery member of the method (a) above has disadvantages both in mass productivity and in the surface properties for the material requiring high surface uniformity as the delivery member, even if it is produced in an automated production line: one coating robot is not capable of coating accurately a plurality of members simultaneously, and the surface state of the coating film tends to become nonuniform owing to diffusion of the paint.
The delivery member of the method (b) above may cause difficulty in charging and discharging of the recording medium owing to deterioration and deformation of the rubber with time and the decrease of the outside diameter accuracy during repeated use, and problems in mass productivity because of the low of the commercial value, the long production steps and low production efficiency, resulting in high production cost.
The delivery member of the method (c) above needs to be treated for rust-prevention in the subsequent step since the surface is liable to rust at the surface. In this case, the metal is plated on the sand-blasted surface having low outside diameter accuracy, resulting in further less accurate outside diameter, and the increase of the manufacturing steps causes cost increase, thus being not suitable for mass production. Further, a delivery member which is roughened at the surface by laser machining to give higher friction coefficient has to be machined one by one at a time with a long machining time, which is not suitable for mass production.
The delivery member of the method (d) above is poor in adhesion and uniformity of the alumina, and in the final outside diameter accuracy, and is limited in mass production of uniform quality of the products.
In the production of the delivery member of the method (e) above, namely composite plating, the bath is liable to be contaminated with impurity to become unstable and is not suitable for continuous use. Further, the working cost is disadvantageously high because of the cost of the plating liquid and the poor dispersibility.